Clamping assembly and a hydraulic coupler comprising it

ABSTRACT

A coupler which is adapted to be connected to a complementary device for the transfer of a fluid between the coupler to the complementary device comprises a body through which the fluid is allowed to flow, at least one seal for providing a fluid-tight seal between the coupler and the complementary device, and a protecting device for the seal. The protecting device is movable between a first position before connection in which the protecting device projects beyond the seal in the direction of connection, and a second position after connection in which the protecting device no longer projects beyond the seal. The coupler also includes a damper for urging the protecting device towards its first position.

This application is a continuation of U.S. patent application Ser. No.10/499,463 filed on Jun. 18, 2004, which is based on PCT PatentApplication No. PCT/EP2002/014869 filed on Dec. 19, 2002.

BACKGROUND OF THE INVENTION

The present invention relates in a general way to couplers.

As is well known, a coupler is a mechanical assembly comprising clampingmodules, intended in particular for applying a pre-clamping force so asto provide mechanical linkage and fluid-tightness between an articulatedproduct loading and unloading arms, in particular for fluid products,for example petroleum products (liquefied natural gas etc.), and acomplementary means installed on a ship.

The present invention relates more particularly to the case when thecoupler is a hydraulic coupler with several clamping modules, inpractice three or more, capable of conveying liquid products at very lowtemperatures (down to −196° C.).

According to a known arrangement, each clamping module comprises aclamping jaw designed for connecting the coupler to a complementarymeans, such as a manifold, and an actuating system proper to the saidjaw and comprising a device of the screw/nut type driven by a motor. Thejaw is carried by a system of rods articulated at one of its ends, on asupport, the actuating system acting upon the system of rods in order toimpel the jaw towards a clamping position or to bring it back to aresting position.

However, in devices of this type that are already known, the forcestransmitted by the rods depend on the thickness of the manifold flangeat the clamping location which, in practice, varies from one location toanother on the flange.

As a result the clamping is often insufficient or excessive.

SUMMARY OF THE INVENTION

The present invention relates, in a general way, to an arrangement thatmakes it possible to provide, more simply and more reliably, clampingeffected by means of the said clamping modules and leading in additionto other advantages.

More precisely, it relates to a clamping assembly for a coupler,comprising at least one clamping module having a clamping jaw designedfor connecting the coupler to a complementary means, and an actuatingsystem proper to the said jaw and comprising a device of the screw/nuttype driven by a motor, characterized in that the actuating system isconnected directly to the jaw and the said jaw is mounted on a supportin such a way that it can swivel about a fixed point defined by the saidsupport, the latter being intended to be fixed to the coupler.

In other words, the actuating system acts directly upon the clampingjaw. Having eliminated an intermediary (the rods), it becomes possibleto obtain much greater clamping forces than previously, with a systemthat is simpler and more reliable than the known systems. Moreover, withthe clamping assembly according to the invention, the coupler can beused in more situations.

According to preferred characteristics relating to this arrangement:

-   -   the device of the screw/nut type is articulated on the jaw at a        second point located a fixed distance from the said fixed point;        and/or    -   the device of the screw/nut type comprises a screw that engages        in a bush with an internal thread and is driven by the motor by        means of a chain; and/or    -   the coupler is a hydraulic coupler and the motor is a hydraulic        motor; and/or    -   the actuating system is carried by the support.

Furthermore, the arrangement according to the invention lends itselfadvantageously to a development that is original per se, according towhich the assembly comprises several clamping modules whose motors havea fluid connection to a hydraulic unit comprising a fluid distributioncircuit and control means designed for controlling the supply of fluidto the motors by the hydraulic unit, so as to cause the jaws associatedwith the motors to swivel, according to a serial arrangement of themotors so long as the jaws do not exert any clamping force on thecomplementary means and according to a parallel arrangement of themotors when the said jaws exert a clamping force.

This development gives a high speed of maneuver (serial arrangement ofthe motors), as well as a large clamping force at the appropriate time(parallel arrangement of the motors).

According to preferred characteristics relating to this development:

-   -   the controlling means are, in addition, able to control supply        to the motors according to a parallel arrangement so as to        overcome the clamping force applied by the jaws to the        complementary means, during unclamping of the jaws; and/or    -   the controlling means are sensitive to the increase in pressure        in the hydraulic unit, resulting from the clamping force applied        by the jaws to the complementary means, and are able to generate        the transition from a serial arrangement of the motors to a        parallel arrangement of them when the pressure reaches a        predetermined value; and/or    -   the controlling means comprise a slide valve provided with a        return spring and a pressure limiter with a return spring,        installed upstream of the slide valve in the fluid distribution        circuit and with fluid connection to the said slide valve;        and/or    -   the hydraulic unit comprises a selector installed in the circuit        so as to provide fluid connection between the inlet of the first        of the motors in the direction of feed of the latter and the        pressure limiter, the fluid distribution circuit supplying the        motors according to two opposite directions depending on whether        it is operating in clamping or unclamping; and/or    -   the fluid distribution circuit comprises a main unit for supply        of oil constituting the said fluid.

The arrangement according to the invention also lends itself to anotherdevelopment that is original per se, and can be combined advantageouslywith the preceding one, and according to which the coupler comprisessealing means that are intended to ensure fluid-tightness of theconnection of the coupler to the complementary means, means forprotecting the sealing means, movable between a first position beforeconnection, in which the said protecting means go beyond the sealingmeans in the direction of connection, and a second position afterconnection, in which the said protecting means are no longer projectingrelative to the sealing means, and damping means that permanently exerta force on the protecting means impelling them towards their firstposition.

With this development there is maximum limitation of the risks connectedwith relative movements and impacts at the time of connection.

According to preferred characteristics relating to this development:

-   -   the coupler comprises means that hold back the protecting means,        preventing the said protecting means from going beyond the first        position in the direction of connection; and/or    -   the sealing means comprise at least one ring seal and the        protecting means comprise a movable ring that surrounds the seal        or seals; and/or    -   the sealing means comprise at least one ring seal and the        protecting means comprise several thrusters encircling the seal        or seals; and/or    -   the damping means consist of a single spring washer, helical        springs, spring washers, gas spring jacks or hydraulic dampers        interposed between the protecting means and the body of the        coupler.

The invention also relates to a hydraulic coupler, comprising a clampingassembly as defined above and fixed to the body of the said coupler.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantages of the invention will become clearerfrom the description that is to follow, by way of an example, referringto the appended schematic drawings, where:

FIG. 1 is a side view with partial section of a hydraulic couplerequipped with a clamping assembly according to the invention and acomplementary means, in the non-connected position;

FIG. 2 is a view similar to FIG. 1, and shows the connected position ofthe hydraulic coupler and of the complementary means;

FIG. 3, on a larger scale, is a top view with partial section of theclamping module in FIG. 2;

FIG. 4 is a view in longitudinal section of the top half of the frontpart of the coupler in FIGS. 1 and 2 and illustrates the protectingmeans of the sealing means of the said coupler; and

FIGS. 5 to 10 are schematic diagrams of the hydraulic unit supplying themotors of the clamping modules according to the invention, andillustrate the various stages in operation of this unit.

DETAILED DESCRIPTION OF THE INVENTION

In the embodiment shown, the hydraulic coupler 10 according to theinvention comprises a clamping module 11 having a clamping jaw 12designed for connecting the coupler 10 to a complementary means 13, andan actuating system 14 proper to the said jaw and comprising a device ofthe screw/nut type 15 driven by a motor 16.

In practice, the clamping modules are three in number, fixed to theperiphery of hydraulic coupler 10 and distributed uniformly around thelatter and constituting a clamping assembly by which coupler 10 can beconnected to the complementary means 13. The said complementary means 13is, here, a manifold, which can be replaced with a closing cover whenthe loading arm equipped with coupler 10 is to be put in the storageposition.

As the actuating system 14 is well-known, it will not be described indetail here.

It will simply be pointed out that in the embodiment illustrated (seeFIG. 3), the device of the screw/nut type 15 comprises a screw 17 thatengages in a bush with an internal thread 18 and is driven by the motor16 by means of a chain 19 transmitting the rotary motion of motor 16 toscrew 17 by means of a driving sprocket 20 rigidly locked with theoutput shaft of motor 16 and a driven sprocket 21 integral with a pieceof shaft 22 that is an extension of screw 17. The latter is housed in acylindrical casing 23, to which a housing 24 is fixed, for housing thechain 19 and sprockets 20 and 21, the motor 16 being fixed to the saidhousing 24.

Furthermore, the bush with internal thread 18 is slidably guided in thecylindrical casing 23.

According to the invention, each jaw 12 has a swivel mounting on asupport 25 about a fixed point 26 defined by the said support 25, thelatter being fixed to the hydraulic coupler 10, in the present case bywelding.

The device of the screw/nut type 15 is also articulated on jaw 12 at asecond point 27 located a fixed distance from point 26 by means of acylindrical component 28 which is fixed to one end of the bush 18 and isconfigured to receive a spindle (not shown in FIG. 3).

The actuating system 14 in its turn is swivel mounted on support 25 bymeans of spindle-receiving disks 29 fixed on the cylindrical casing 23.

It should also be pointed out that support 25 is formed by two plates 30that which are symmetrical relative to a longitudinal median planeintersecting at right angles the swiveling axes of clamping module 11and which receive between them the actuating system 14 as well as thejaw 12, which is, in turn, formed by two plates 31 that are symmetricalrelative to the said plane.

More precisely, each plate 30 of support 25 comprises a vertical section32 (see FIGS. 1 and 2), on which the actuating system 14 isswivel-mounted, and a horizontal section 33 defining the fixed point 26.

Each horizontal section 33 is reinforced, in the region of the fixedpoint 26, by an outer plate 34 welded onto the adjacent plate 30.

Each plate 31 of jaw 12 comprises, according to a general configurationof a right-angled triangle, two holes through which spindles pass, onefor the spindle housed in cylindrical component 28 and defining theswivel point 27 and the other for the journal 35 defining the fixedswivel point 26. Holes aligned with the aforementioned holes are ofcourse also provided in the support plates 25.

A clamp 36 carrying a sliding block 37 is fixed to jaw 12. It, too, isformed from two plates 38 that are symmetrical relative to the aforesaidplane, each being fixed to one of the plates 31 forming jaw 12.

It should be pointed out, in this connection, that these plates 38extend along the side of the substantially triangular plates 31 closestto the hydraulic coupler 10 and they also have a hole through whichjournal 35 passes. Furthermore, it should also be noted that the slidingblock makes it possible to connect the hydraulic coupler 10 to severaldifferent diameters of flanges 39 of manifold 13. In practice, and suchis the case in the embodiment shown here, these diameters are generallythree in number.

Thus, the jaw 12 is pivotably mounted on the support 25 about a lowfixed point 26 (proximal point with respect to the coupler 10) definedby the support 25, the device of screw/nut type 15 is articulateddirectly on the jaw 12 at a high point 27 (distal point with respect tothe coupler 10) defined by the jaw 12 and situated at a fixed distancefrom the low fixed point 26 and the actuating system 14 is itselfarticulated on the support 25 in the vicinity of the high point 27.

It will also be noted that the clamp 36 of the jaw 12 forms a projectionroughly with respect to a third point defined by the jaw 12 and forminga triangle with the low and high points.

Furthermore, the extension of each jaw 12 and of the device 15 ofscrew/nut type which is associated with it is in the same generaldirection as that of the body, here cylindrical, of the coupler 10.

Moreover, hydraulic coupler 10 is equipped with a system that protectsits seals, as can best be seen in FIG. 4.

In the embodiment shown, the hydraulic coupler 10 comprises a protectingring 40 that is movable relative to the annular front face 41 of coupler10 and is positioned around ring seals 42 and 43 housed in correspondinggrooves in the body 45 of coupler 10. Compression springs, only one ofwhich is visible in FIG. 4, bearing the reference sign 44, are placedbetween this ring 40 and the body 45 of coupler 10 and act in the axialdirection, permanently holding the ring 40 and the body 45 of coupler 10apart.

In practice, the ring has a groove 46 forming a seat for one of the endsof these springs 44, whereas the body 45 of coupler 10 has an oppositeface 47 that is recessed relative to the front face 41 and forms a seatfor the opposite end of the said springs 44.

When coupler 10 is in the closed position (see FIG. 2) on a flange 39 ofmanifold 13, the springs 44 are compressed and flange 39 is in contactwith seals 42 and 43 and a front face 48 of ring 40 located on the sideof the latter opposite to that with the groove 46.

When coupler 10 is in the open position (see FIG. 1), ring 40 abutsagainst the centering guides 49 of coupler 10, just one of which isvisible in FIG. 4. In this position, the springs 44 are pre-compressedand not completely released.

When coupler 10 is brought closer to flange 39, the seals 42 and 43 arerecessed relative to the face 48 of ring 40 and so are protected fromany impacts due to flange 39 to be connected. The energy of theseimpacts is absorbed by the work of compression of springs 44.

Then, during closing of the jaws 12 of coupler 10, springs 44 arecompressed by the clamping force exerted by the clamping modules 11. Itwill be appreciated, in this connection, that the reactive force of ring40 on flange 39, created by springs 44, makes it possible to eliminateany relative radial movements that could, without this protectingsystem, cause deterioration of seals 42 and 43 by friction.

In the closed position, the supporting force of seals 42 and 43 is equalto the clamping force of jaws 12 minus the force of compression ofsprings 44. In practice, therefore, the clamping force of jaws 12 mustbe chosen in such a way that it is much greater than the force ofcompression of springs 44.

Moreover, various types of damping springs can be used:

-   -   a single spring washer with the same diameter as the groove of        ring 40,    -   one or a number of helical springs,    -   one or a number of spring washers,    -   gas spring jacks or hydraulic dampers.

According to a variant of this protecting system, ring 40 can bereplaced with thrusters positioned around seals 42 and 43 and connectedto the damping means defined above.

Other solutions for abutment can also be used, such as pins fixed to thebody 45 and equipped with a head retaining ring 40.

For supplying oil to the hydraulic motors 16 of the clamping modules 11,a hydraulic unit with a fluid distribution circuit is also provided, asis best seen in FIGS. 5 to 10.

The said hydraulic unit 50 comprises, according to the invention, aslide valve 51 provided with a return spring and a pressure limiter 52with a return spring, installed upstream of valve 51 in the distributioncircuit and with fluid connection to the said valve 51.

The hydraulic unit 50 also has a selector 54 arranged in the fluiddistribution circuit to provide fluid connection between the inlet ofthe first of the motors 16 ₁-16 ₃, in their direction of supply, andpressure limiter 52. Depending on whether the unit is acting forclamping or unclamping of jaws 12, the first motor is motor 16 ₁ or 16₃.

The said hydraulic unit 50 is in addition supplied with oil by a centralunit 55 comprising a distributor 56 and two non-return valves withcontrollable throttling 57, connected respectively to a closing line andan opening line connecting the central unit 55 to hydraulic unit 50.

As can be seen in FIGS. 5 to 10, the fluid distribution circuit ofhydraulic unit 50 is designed for supplying all the motors 16 ₁-16 ₃with the oil flow and pressure that they require, and at any time.According to the invention, for this purpose the hydraulic unit 50operates according to the series/parallel principle.

More precisely, during the stages of approach for closing, the clampingmodules 11 with jaws 12 ₁-12 ₃ maneuver rapidly. For this, the hydraulicunit operates in series (low pressure and high flow rate). For clampingonto a flange 39, the unit operates in parallel (high pressure and lowflow rate).

When coupler 10 is clamped on a flange 39, for unclamping it thehydraulic unit 50 has to supply a lot of pressure to each of the motors16 ₁-16 ₃: therefore it operates in parallel. As soon as all of theclamping modules 11 are unclamped, hydraulic unit 50 changes to seriesoperation to give quick opening.

Series/parallel changeover of hydraulic unit 50 occurs in relation tothe forces transmitted and to be transmitted to the clamping modules 11.It is the slide valve inside hydraulic unit 50 that permits changeovereither to series operation or to parallel operation. The position ofthis slide valve depends on the forces transmitted by the clampingmodules 11. When there is no force acting on the clamping modules 11,hydraulic unit 50 puts itself in the series position. As soon as aclamping module 11 forces or presses against something (flange, stopetc.), the supply pressure of the series circuit increases and moves theslide valve towards its position for supplying motors 16 ₁-16 ₃ inparallel, so as to deliver the maximum available pressure to each ofthese motors. Modules 11 then have a low speed but a high transmissibleforce. Conversely, when there is no longer any force on anyone of theclamping modules 11, the internal pressure of hydraulic unit 50decreases and thus allows the slide valve to move to its seriesposition.

The operation of hydraulic unit 50 will now be described in greaterdetail, referring to FIGS. 5 to 10.

FIG. 5: (Coupler 10 in the Open Position)

No movement is “demanded” from coupler 10. There is no circulation ofoil in the hydraulic circuit. In this state (rest), the hydraulic unitis systematically in the series position. The slide valve of unit 50 ispushed towards the left by its return spring.

FIG. 6: (Coupler 10 in Course of Closing)

During this approach phase, no force of resistance is received by theclamping modules 11. Hydraulic unit 50 therefore operates in series, sothat there is rapid movement of modules 11. The oil leaving motor 16 ₁goes into motor 16 ₂ after briefly passing through hydraulic unit 50,then leaves it again and enters the unit and then motor 16 ₃, beforereturning to the central unit 55.

FIG. 7: (Coupler 10 in the Clamping Phase)

During the clamping phase, a resistance appears at the jaws 12 ₁-12 ₃,giving rise to an increase in the hydraulic pressure of the circuit. Thepressure will therefore push the valve slide in hydraulic unit 50towards the right in the diagrams. At that moment, unit 50 willtherefore change over to the parallel position, which means that eachmotor 16 ₁-16 ₃ will be supplied directly by the central unit 55 and notby the preceding motor. The flow will therefore be divided as a functionof the number of motors. On the other hand the pressure will increase.At the outlet of each motor 16 ₁-16 ₃, the oil returns directly to thecentral unit 55.

FIG. 8: (Coupler 10 Closed)

Once coupler 10 is closed, oil circulation stops. The slide valve inunit 50 therefore goes back to the series position (displaced towardsthe left in the diagrams), under the action of its return spring.

FIG. 9: (Unclamping of Coupler 10)

At the moment of opening, it is necessary to overcome the forces due toclamping. These forces have the effect of raising the pressure withinthe hydraulic circuit, and therefore of causing unit 50 to change to theparallel position (the pressure displaces the valve slide of unit 50towards the right in the diagrams). Each jaw 12 ₁-12 ₃ therefore has ahigh oil pressure at its disposal, which enables them to be unclamped.

FIG. 10: (Opening of Coupler 10)

Once coupler 10 is unclamped, there is no longer any force to beovercome. The internal pressure of the hydraulic circuit decreases,causing the valve slide in unit 50 to move towards the left in thediagrams. During this opening phase, unit 50 is in the series position,permitting rapid movement of jaws 12 ₁-12 ₃.

In practice, it may be noted, as a non-limiting example, that for amaximum outlet pressure of central unit 55 of about 150×10⁵ Pa, thepressure value causing the slide to move from a position in series to aposition in parallel is about 80-90×10⁵ Pa.

In the embodiment shown in FIGS. 5 to 9, movement of the slide from aseries position to a parallel position depends on whether the pressurelimiter is in the open or closed position, these positions depending intheir turn on the return spring chosen for the said limiter 52.

However, in other embodiments it would be possible for the slide valve51 to be designed so that it changes from one position to the other byan appropriate choice of return spring for it. In this case it will notbe necessary to employ a pressure limiter 52.

It would also be possible, in another embodiment, to employ detectors ofthe position of the jaws or of the pressure at motors 16 ₁-16 ₃ andelectric control of slide valve 51.

The actuating system 14 may also be borne by a support different to thaton which is mounted the jaw 12 associated with it.

The support or supports may, moreover, also be formed integrally withthe coupler.

Of course, the present invention is not limited to the embodiment thathas been described and illustrated, but encompasses all variants ofexecution.

What is claimed is:
 1. A coupler which is adapted to be connected to acomplementary means for the transfer of a fluid between the coupler andthe complementary means, the complementary means comprising a tubularflow member having a first transverse end flange defining a firstannular end face, the coupler comprising: a body which is releasablyconnectable to the tubular flow member, the body having a secondtransverse end flange defining a second annular end face which engagesthe first annular end face when the body is connected to the flowmember; at least one seal which is mounted on the second annular endface for providing a fluid-tight seal between the first and secondannular end faces; means for protecting the at least one seal; theprotecting means comprising a ring which is mounted concentrically overthe second transverse end flange and is movable by the complementarymeans between a first position before connection in which the ringprojects beyond the at least one seal in the direction of connection,and a second position after connection in which the ring no longerprojects beyond the at least one seal; and damping means positionedbetween the second end flange and the ring for urging the ring towardsits first position wherein the ring does not engage the at least oneseal in either its first or second position.
 2. The coupler of claim 1,further comprising retaining means for preventing the ring fromprojecting beyond the first position in the direction of connection. 3.The coupler of claim 1, wherein the at least one seal comprises at leastone ring seal and the ring encircles the ring seal.
 4. The coupler ofclaim 3, wherein the damping means comprises one selected from the groupconsisting of a number of spring washers, a number of helical springs, anumber of gas spring jacks and a number of hydraulic dampers, each ofwhich is interposed between the ring and the second end flange.
 5. Acoupler which is adapted to be connected to a complementary means forthe transfer of a fluid between the coupler and the complementary means,the complementary means comprising a tubular flow member having a firsttransverse end flange defining a first annular end face, the couplercomprising: a body which is releasably connectable to the tubular flowmember, the body having a second transverse end flange defining a secondannular end face which engages the first annular end face when the bodyis connected to the flow member; at least one seal which is mounted onthe second annular end face and which provides a fluid-tight sealbetween the first and second annular end faces when the coupler isconnected to the complimentary means; means movably mounted on the bodyfor protecting the at least one seal; the protecting means being movableby the first transverse end flange between a first position beforeconnection in which the protecting means projects beyond the at leastone seal in the direction of connection, and a second position afterconnection in which the protecting means no longer projects beyond theat least one seal; and damping means for urging the protecting meanstowards its first position.
 6. The coupler of claim 5, furthercomprising retaining means connected to the body for preventing theprotecting means from projecting beyond the first position in thedirection of connection.
 7. The coupler of claim 5, wherein the at leastone seal comprises at least one ring seal and the protecting meanscomprises a movable ring which encircles the ring seal.
 8. The couplerof claim 5, wherein the damping means comprises one selected from thegroup consisting of a number of spring washers, a number of helicalsprings, a number of gas spring jacks and a number of hydraulic dampers,each of which is interposed between the protecting means and the body ofthe coupler.